A compressed gas-blast circuit-breaker of this type, regarding its contact arrangement and configuration, is described in, for example, German Patent No. 25 32 088. In this circuit breaker the first, actuatable arcing contact has an annular configuration and is supported by a switching tube through which switching gases resulting from the breaking operation arrive in a discharge volume, which is a low-pressure chamber. In this context, the contact arrangement has a compression device assigned to it, which can be connected to the discharge volume via a fill-up valve, as is also described in German Patent No. 26 18 087.
Irrespective of how compressed gas-blast circuit-breakers of this type are configured, i.e., even if the arcing contacts have a heating space assigned to them that is connected to the compression device via a non-return (stop) valve (a compressed gas-blast circuit-breaker of this type, for example, is described in German Patent 38 33 564), the flow of switching gases resulting from the breaking operation through the switching tube supporting the first, actuatable arcing contact into the discharge volume is always associated with a disadvantage affecting the breaking capacity of the compressed gas-blast circuit-breaker. This is true particularly because in response to a high-speed re-closing, it is unavoidable that the non-ionized quenching gas present in the fill-up valve mixes with the switching gas in the discharge volume contaminated by decomposition products and by vaporized materials.